Do I need a permit to build a deck?

Two permits, two questions

The development permit asks a zoning question: is a structure of this size allowed in this part of your lot? It is about setbacks, yard, site coverage and your neighbours. It does not care how the deck is built.

The building permit asks a structural question: will it stand up and is it safe to walk on? It is about footings, spans, guards and stairs, and it comes with inspections.

You can need one without the other. A low front yard deck can need development approval and no building permit. A 900 mm (35 7/16 in) back yard deck can need a building permit and no development approval.

The Edmonton thresholds

City of Edmonton, for an uncovered deck serving a single dwelling unit. Other municipalities use different numbers, and this page is an explanation, not an application.

The exception that catches low decks

A deck 500 mm (19 11/16 in) off the lawn sounds exempt, and usually is. But if the surface within 1.2 m (47 3/16 in) of the deck edge drops more than 600 mm (23 9/16 in), over a retaining wall or down a slope steeper than 1 in 2, then the code measures to that lower surface. A guard is required, and with it a building permit.

This is the single most common way a homeowner finds out mid build that the deck was never exempt.

When drawings are required

A simple rectangular deck at a normal height can often be permitted from the application form alone. Drawings and plan review come in when the reviewer cannot check compliance without them:

• Site plan if the lot is at the top of a bank, the house is a designated heritage building, or the deck is 1.8 m (5 ft 10 13/16 in) or higher.
• Multi level decks, because the beam arrangement is more complicated than a single platform.
• Irregular shapes and openings in the walking surface, because of the doubled and tripled headers and trimmers involved. Cutting a corner joist back at an angle to soften a sharp corner is specifically exempted, as long as you do not cut back past the outward face of the beam.
• Over 18 ft out from the house, because it will need more than one beam or a joist span over 4.9 m (16 ft 15/16 in).
• Over 30 ft wide.
• Over 55 square metres (592 square feet), which also brings an engineer stamped foundation design whatever the foundation type.
• Heavy loads: hot tub, pool, built in fireplace or large barbecue, a roof, a gazebo.
• Unconventional materials: engineered wood such as I joists or LVL, steel, masonry, concrete.
• More than 1.8 m (5 ft 10 13/16 in) high, engineer stamped foundation. More than 3.6 m (11 ft 9 11/16 in), engineer stamped everything.
• Unusual use, such as a home based business gathering area, because the loading is different.

Hot tubs, specifically

A hot tub on the deck is an extraordinary load, so the joists, beam, posts, foundation and every connection including the ledger need an engineer stamped design. Setting the tub on the ground and framing the deck around it normally avoids that, and Edmonton says so directly, with the condition that every service point on the tub stays accessible. The electrical circuit is its own permit and its own licensed trade either way.

Why the permit is worth having even when it is optional

Where a permit is not required you may still take one out. The work has to meet the requirements regardless, an inspection follows, and a record of the work is made. That record is what a buyer, an insurer and the next owner's home inspector will look for. A deck with no record is a deck somebody will have to prove, usually at the worst possible moment.

What to have ready before you apply

1. Deck height at the worst corner, measured, not estimated.
2. Width parallel to the house and length out from it.
3. Where it sits on the lot, and which yard that is.
4. Joist size and spacing, beam make up, post size, post spacing.
5. Foundation type and depth.
6. Guard and stair details, including the manufactured guard paperwork if you are using one.
7. Anything heavy that is going on it.

Everything in that list has an answer on this site, and most of them have a demonstration that works it out for you.